Liquid containers for producing and/or storing liquids (or fluids) provided for drinking consumption, especially alcohol-containing beverages, such as beer, wine, fruit wine, whisky, schnapps, fermented beverages, such as for example Bionade™ or Kombutcha™, mixed beverages, such as juice spritzer or beers that have been modified tastefully using additional flavouring substances, are known. The known liquid containers, such as barrels, are typically made of one of the following substances resp. raw materials: wood, steel (especially stainless steel), plastics or concrete. In a traditional method for producing wine, also amphoras made of burned clay (for example natural coloured earthenware) resp. stoneware are used.
In the production of alcohol-containing beverages, a yeast resp. a yeast culture is mixed into a sugar-containing liquid, such as grape juice or fruit juice, containing fructose and being provided in a liquid container, and thereby the fermentation of the grape juice or fruit juice to grape wine (wine) or fruit wine is initiated. In the fermentation, the fructose is converted partially to alcohol, in a majority to ethanol, in an exothermic reaction in which heat is generated. Depending on the holding capacity of the liquid container and the material, from which it is made, it may be necessary to discharge the emerging heat by means of an additional external cooling system, in which a flowing cooling liquid, such as for example water, brought in contact with a wall of the container. This holds often particularly for liquid containers that are made of plastics, so as to ensure that the plastics does not macerate under the influence of the heat.
The sugar (or fructose)-containing liquid, such as the grape or fruit juice, may also contain an acid, such as fruit acid. Therefore, the material, of which the liquid container is made, must be chosen or machined such that its surface that comes in contact with the liquid is acid-resistant. In this respect it is disadvantageous e.g. in the production of wine in barrels made of concrete, such as they are increasingly used e.g. in France, that concrete contains chalk (or calcium carbonate), a part of which dissolves partially under the influence of the fruit acid, migrates partially into the liquid, another part of which deposits on the inner wall surface of the concrete barrel. Therefore, concrete barrels are cleaned with citric acid before filling in the grape juice in order to remove the precipitated chalk residues.
For barrels made of wood, which are traditionally used in the production and storage of wine, it is disadvantageous on one hand side, that the barrels either have to be replaced after about five to seven cycles of wine production, because the inner surface of the wood has been affected, or have to be toasted (subjected to a heat treatment) in order to make the surface again suitable for the production process and/or to regenerate them. On the other hand side, the conservation of wooden barrels that are not filled with wine is problematic and requires additional measures, such as the enrichment of the air contained in the barrel with sulphur (so-called dry conservation) or the filling in of sulphur water into the barrel (so-called wet conservation).
Adepts and/or wine growers know that in the production of wine in barrels made of stainless steel, it is difficult to produce “great” wines, because among the materials (wood, stainless steel, plastics, concrete) that are common to date for manufacturing the barrels, stainless steel is the most neutral and due to the relatively smooth inner surface, only little gas exchange can take place with the filled in liquid (e.g. grape juice).